Celluloid has been used as a material of a table tennis ball since around 1930. Celluloid, however, has drawbacks in that it is extremely flammable, readily ignited, for example, by friction, readily deteriorated, for example, by light, and less durable. Thus, in factories in which celluloid is used, celluloid has often caused a fire by ignition due to its autoreactivity and, in Japan, celluloid is designated as a combustible regulated subject (hazardous material in Category V) according to Fire Service Act, and the method of producing, storing, and handling celluloid is strictly prescribed.
In addition, by the influence of light, oxygen, or the like over a long period of time, celluloid is dissociated into cellulose and nitric acid and deteriorated and, consequently, it tends to cause “stickiness” and “cracks” and is difficult to store stably for a long period of time. Furthermore, the strongly acidic gas (nitric acid) that generates during the dissociation process may corrode, for example, the surrounding celluloid and metals.
For table tennis balls, there is a standard established by International Table Tennis Federation (hereinafter referred to as ITTF). This standard is disclosed in Technical Leaflet T3 of ITTF (The Ball (Version for 40 mm Balls) Technical Leaflet T3). The following is an excerpt therefrom.
Excerpt from ITTF Technical Leaflet T3